1. Field of the Invention
The present disclosure relates to flexographic printing and, more specifically, to sleeves used with flexographic print presses.
2. Description of Related Art
Flexographic printing is commonly done on print presses in high speed automated environments. Such presses commonly include a variety of components configured to accept a moving web of material and to dispose a repeated image onto the web as it passes through the press. In such presses, the web is typically fed between a pair of cylinders acting in concert to dispose, for example, an ink-based or dye-based image on the web as it passes therebetween at a desired rate and pressure. For example, known print presses may include a cylindrical mandrel onto which a print sleeve may be disposed. The print sleeve may include a raised portion onto which ink may be disposed to form a corresponding image on the web as it passes adjacent to the raised portion. The raised portion may be formed integrally with the print sleeve or, alternatively, a printing plate may be adhered to and/or otherwise mounted to the print sleeve to form the image.
In known print presses, the print sleeve may be disposed at a desired location along the mandrel to facilitate an accurate and/or otherwise desirable location of the repeated image on the web. To facilitate mounting the cylindrical print sleeve on the mandrel and desirably positioning the print sleeve along the mandrel, a flow of pressurized air such as, for example, shop air may be directed through the mandrel to an inner surface of the print sleeve. To direct such a flow of pressurized air through the mandrel to the sleeve, prior art mandrels typically include a hollow portion fluidly connected to orifices formed by the outer surface of the mandrel to direct the flow out of the mandrel. Directing the flow in this way forms, for example, an air pocket between an inner surface of the print sleeve and the outer surface of the mandrel. At least a portion of known print sleeves may be circumferentially expandable and, thus, forming an inner pocket between the print sleeve and the mandrel may expand at least a portion of the print sleeve to allow the sleeve to slide more freely along the surface of the mandrel until the sleeve is disposed at the desired location. Once the print sleeve has been desirably positioned, the flow of air may be removed from the mandrel, thereby causing the print sleeve to contract and substantially lock in place on the mandrel.
However, prior art print sleeve/mandrel assemblies suffer from several deficiencies. For example, it is difficult and expensive to manufacture mandrels that are both robust enough to be used in a wide range of printing applications in manufacturing environments and that include a network of air passages appropriate for directing a flow of pressurized air from within the mandrel to an outer surface of the mandrel. In addition, because such orifices must be primarily disposed proximate a leading edge of the mandrel to facilitate disposing the print sleeve on the mandrel, prior art print sleeves must be substantially the same length as the mandrel so that a portion of the inner surface of the print sleeve is always covering the mandrel orifices while the print sleeve is disposed on the mandrel. It is understood that moving the print sleeve past the orifices of the mandrel will cause the print sleeve to lock in place on the mandrel and will leave the operator with no way of removing the print sleeve from the mandrel. However, manufacturing print sleeves that are substantially the same length as the air-fed mandrel on which they will be used can be extremely costly and may be unnecessary for applications in which the images being applied by the print sleeves are substantially narrower than the overall length of the mandrel.
The exemplary embodiments described herein solve the deficiencies of the prior art.